[PATCH 5/5] dmaengine: sprd: Add 'device_config' and 'device_prep_slave_sg' interfaces

[Baolin Wang]

This patch adds the 'device_config' and 'device_prep_slave_sg' interfaces
for users to configure DMA.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
 drivers/dma/sprd-dma.c |   48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index f8038de..c923fb0 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -869,6 +869,52 @@ static int sprd_dma_config(struct dma_chan *chan, struct sprd_dma_desc *sdesc,
 	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
 }
 
+static struct dma_async_tx_descriptor *
+sprd_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		       unsigned int sglen, enum dma_transfer_direction dir,
+		       unsigned long flags, void *context)
+{
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_config *slave_cfg = &schan->slave_cfg;
+	struct sprd_dma_desc *sdesc;
+	struct scatterlist *sg;
+	int ret, i;
+
+	/* TODO: now we only support one sg for each DMA configuration. */
+	if (!is_slave_direction(slave_cfg->config.direction) || sglen > 1)
+		return NULL;
+
+	sdesc = kzalloc(sizeof(*sdesc), GFP_NOWAIT);
+	if (!sdesc)
+		return NULL;
+
+	for_each_sg(sgl, sg, sglen, i) {
+		if (slave_cfg->config.direction == DMA_MEM_TO_DEV)
+			slave_cfg->config.src_addr = sg_dma_address(sg);
+		else
+			slave_cfg->config.dst_addr = sg_dma_address(sg);
+	}
+
+	ret = sprd_dma_config(chan, sdesc, slave_cfg);
+	if (ret) {
+		kfree(sdesc);
+		return NULL;
+	}
+
+	return vchan_tx_prep(&schan->vc, &sdesc->vd, flags);
+}
+
+static int sprd_dma_slave_config(struct dma_chan *chan,
+				 struct dma_slave_config *config)
+{
+	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
+	struct sprd_dma_config *slave_cfg =
+		container_of(config, struct sprd_dma_config, config);
+
+	memcpy(&schan->slave_cfg, slave_cfg, sizeof(*slave_cfg));
+	return 0;
+}
+
 static int sprd_dma_pause(struct dma_chan *chan)
 {
 	struct sprd_dma_chn *schan = to_sprd_dma_chan(chan);
@@ -996,6 +1042,8 @@ static int sprd_dma_probe(struct platform_device *pdev)
 	sdev->dma_dev.device_tx_status = sprd_dma_tx_status;
 	sdev->dma_dev.device_issue_pending = sprd_dma_issue_pending;
 	sdev->dma_dev.device_prep_dma_memcpy = sprd_dma_prep_dma_memcpy;
+	sdev->dma_dev.device_prep_slave_sg = sprd_dma_prep_slave_sg;
+	sdev->dma_dev.device_config = sprd_dma_slave_config;
 	sdev->dma_dev.device_pause = sprd_dma_pause;
 	sdev->dma_dev.device_resume = sprd_dma_resume;
 	sdev->dma_dev.device_terminate_all = sprd_dma_terminate_all;
-- 
1.7.9.5